Factory officials and safety investigators are struggling to explain how a Bumble Bee tuna plant worker was apparently cooked to death in an oven at the company’s Santa Fe Springs, Calif. facility.

The Whittier Daily News reported that at about 7 a.m. on Oct. 11, 62-year-old Jose Melena was found dead in an oven known as a steamer machine.

“The entire Bumble Bee Foods family is saddened by the tragic loss of our colleague, and our thoughts and prayers are with the Melena family,” Pat Menke, Bumble Bee’s vice president of human resources, said in a statement.

An initial probe by the California Division of Occupational Safety and Health has failed to reveal how the six-year veteran of the plant ended up in the oven. The plant shut down following the incident for an in-depth investigation and re-opened on Monday, the Daily News reported. A full investigation, including visits to the factory, reviews of safety documentation and interviews, will be completed within six months to determine whether health and safety violations occurred, according to OSHA policy.

“This is a horrendous tragedy,” Cal-OSHA spokesperson Erika Monterroza told the Daily News, adding that Bumble Bee could incur civil penalties if a probe uncovers violations. The company could face criminal charges from the Los Angeles County District Attorney’s office as well.

Friends and family gathered at Melena’s home in southern Los Angeles to mourn, CBS Los Angeles reported.

Melena’s son Antonio told CBS that his father was a role model for how to live life, “grateful he had a job, that he could pay his bills and provide food for his family.” The well-kept garden in the Melenas’ front yard, he said, was one of the ways his father set an example “to be honest, truthful and hard working.”

Jose Melena isn’t the first person to fall victim to this type of industrial accident. In March, U.K. outlet The Sun reported that two Austrian men were burned alive in a furnace at an aluminum plant after its automatic door closed behind them and a coworker turned on the switch.